Despite getting my ass handed to me for the better part of 2 hours last night/this morning, the online game play is the by far the way to go.
After we completed the campaign, the fellas took off so I had time to set up the wireless connection so smackette wouldn't have a canniption. For the most part, I didn't see a lag time on the game play, but the voice wasn't all that great, but to me that's no big loss. It could be like that over a wired network for all I know. It was kind of like listening to Markie after a few beers.
Finding a game in the training room wasn't a problem, even at 2 AM PT. On the bigger maps I did some investigation for the most part, like thatguy was saying. On the smaller maps I did some fragging and got whipped pretty badly. There's a big difference between having 4 guys in a room playing each other and 8-16 guys running around - 10 times the action.
I noticed that you can have more than one guy online with just one x-box, which means that I should be online a lot more often, even when the fellas are over. We'll probably never do the 4 player multiplayer again! It's all about live now.
Last note: Microsoft is reporting $125 Million in receipts for day one. That's just a ridiculous number!